Chapter 21.81 — HILLSIDE DEVELOPMENT

The purpose of this chapter is to establish development standards that conserve the natural character of hillside areas, preserve and enhance the scenic hillside amenities of the city, and minimize the environmental impact resulting from extensive grading in visually sensitive areas. Development on hillsides shall be designed to conform to the topographical contours of the site to the extent feasible. Notwithstanding the provisions of this chapter, grading in hillside areas shall be performed in a manner consistent with the applicable provisions of Title 20 (Grading), the recommendations of a licensed civil engineer, and subject to approval of the city engineer.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)

A.

This chapter applies to all development, grading, and construction projects within the city of Paso Robles.

B.

These hillside development standards are in addition to those development standards established in Chapter 21.33 (Residential Zoning Districts), Chapter 21.34 (Commercial, Industrial, and Airport Zoning Districts), Chapter 21.35 (Public Parks, Open Space and Agricultural Zoning Districts), and Chapter 21.36 (Overlay Zoning Districts), except

where the development standards for the primary zoning district are more restrictive than the development standards for hillside areas.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)

A.

"Area of disturbance" means the portion of a project site that is disturbed for development, including any areas disturbed to accommodate structures, foundations, all graded slopes, parking areas, driveways, graded outdoor recreation spaces, and any areas otherwise graded or altered from existing conditions.

B.

"Average slope" shall be calculated consistent with Subsection 21.41.060 (Determining Average Slope).

C.

"Developable area" is defined in Section 21.41.070 (Determining Developable Area).

D.

"Exterior retaining wall" means a retaining wall that faces an exterior property line and/or is not fully screened by a structure.

Figure 21.81.030-1: Exterior Retaining Wall

E.

"Hillside" means those net developable areas with existing slopes of over ten percent.

F.

"Interior retaining wall" means a retaining wall that faces a structure on a lot where the retaining wall is fully screened by said structure.

Figure 21.81.030-2: Interior Retaining Wall

G.

"Mass grading" means the excavation or deposition (cut and fill) of soil across a parcel for the construction of multiple buildings or other improvements. Mass grading sometimes involves the movement of soil across existing or proposed property lines for the purpose of balancing the overall earthwork (the amount of cut and fill) on the site. Mass grading is often used for multiple parcels or pads.

H.

"Pad grading" means the excavation or deposition (cut and fill) of soil to create a relatively flat area on a single parcel for the construction of improvements.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)

A.

General Grading and Building Standards. The area of disturbance (defined in Subsection 21.81.030(A)) shall be limited to the developable area (defined in Section 21.41.070) of a lot.

B.

General Grading Standards.

Grading shall be designed to minimize landform alteration to the extent feasible.

Mass or pad grading is only allowed where it is necessary for the reasonable use of the property and shall be conducted in a manner consistent with the purpose and intent of this chapter, including Paragraph 21.81.040(B)1. and Subsection 21.81.040(C) (Structure Foundations on Slopes).

Grading design shall be based on the concept of contour grading, where the existing landform is maintained or the natural landform pattern is replicated in the case of extensive grading.

The crest of all graded slopes greater than six feet vertical height shall be rounded. Where graded slopes intersect, the ends of each slope shall be horizontally rounded and blended.

C.

Structure Foundations on Slopes. Except as allowed through approval of a modification consistent with Section

be subject to the following standards:

Slopes of Less than Fifteen Percent. Individual pad grading is allowed where the area of disturbance has an existing slope less than fifteen percent.

Slopes Fifteen—Thirty-Five Percent. Where the area of disturbance has an existing slope of between fifteen and thirty-five percent, pad grading is not allowed. Foundations shall incorporate special building techniques designed by a registered engineer or architect, including, but not limited to, split levels, benching, cantilevered, poles, piles, step and stem walls, and other methods designed to minimize soil disruption.

Slopes of More than Thirty-Five Percent. No area of disturbance is permitted on an existing slope greater than thirty- five percent.

D.

Development Standards on Slopes.

Graded Slopes and Retaining Walls.

a.

The maximum vertical height of a graded slope or combination of graded slope and the exposed face of any exterior or interior retaining wall shall not exceed the limits indicated in Table 21.81.040-1 (Slope and Retaining Wall Height).

Table 21.81.040-1: Slope and Retaining Wall Height

Side/Front Yards Rear Yards All Yards

Building Type 2:1 Slope 3:1 Slope 2:1 Slope 3:1 Slope Exposed Max Vertical Max Vertical Exposed Max Vertical Max Vertical Face of ≥4:1 Slope Max Vertical Change (ft.) Change (ft.) Face of Change (ft.) Change (ft.) Retaining Change (ft.) Retaining Walls (ft.) Walls (ft.)

Single-Family and Multi-Family Residential (Sq. Ft.)

Lot size ≤7,000 sq. ft. 4 6 4 6 10 6 unlimited

7,001—9,999 8 10 4 8 12 6 unlimited

≥10,000 12 15 4 12 18 6 unlimited

Nonresidential 12 15 6 12 18 6 unlimited

b.

The minimum distance required between multiple retaining walls shall be less than or equal to the height of the retaining wall as described in Table 21.81.040-1 (Slope and Retaining Wall Height) and as shown in Figure 21.81.040- 1 (Minimum Distance Between Multiple Retaining Walls).

c.

Retaining walls to create building pads shall be constructed of masonry material, textured concrete, or similar material as determined by the review authority.

d.

Setbacks from property lines to graded slopes and retaining walls shall be consistent with the California Building Code.

Figure 21.81.040-1: Minimum Distance Between Multiple Retaining Walls

Stem Walls. The exposed face of a building stem wall shall not exceed nine feet in average height and shall consist of a decorative surface finish compatible with the building architecture or natural hillside character.

Roof Materials. Roofing shall be fire-retardant and shall be neither white nor reflective.

Outdoor Flat Area or Deck for Single-Family Residential Structures. Development of new single-family residences shall include an unobstructed existing or manufactured (graded) area of at least ten feet in depth for the length of a building with a slope not more than five percent. Where the structure is designed to be built into the existing slope, this requirement may be met by providing either a five-foot-wide manufactured area no less than the full width of the dwelling unit, or a deck at least ten feet in depth and no less than the full width of the dwelling unit. The underside of a deck that is three feet or higher above grade shall be screened.

Landscaping. In addition to the standards of Chapter 21.45 (Landscaping and Open Space), landscaping in hillside areas shall comply with the following.

a.

Protection and Use of Existing Vegetation. Development shall protect and retain existing vegetation to the maximum extent possible. Existing groundcover and shrubs shall not be removed from lands with steep slopes (thirty-five

percent or greater) unless necessary for weed abatement to remove fire hazards. When groundcover is removed on any slope, it shall be replaced with other vegetation. Existing groundcover shall be protected from damage during construction.

b.

New Landscaping. All development shall provide new landscaping as follows:

i.

Erosion Control. All graded slopes or slopes cleared of vegetation shall be landscaped with groundcover or other vegetation designed to retain the slope and to mitigate the visual impacts associated with bare ground.

ii.

Architectural Enhancement. Trees and shrubs shall be planted to provide screening under decks, along walls, and as accent features.

iii.

Street Trees. Street trees shall be planted as required by Title 10 (Vegetation).

iv.

Trees on Graded Slopes. Trees shall be planted within the landscaping on graded slopes at a rate of at least one tree per one thousand square feet of graded slope.

v.

Irrigation. All landscaping required for erosion control, trees, and architectural enhancement shall be irrigated. Irrigation design shall be in compliance with Chapter 21.56 (Water Efficient Landscaping).

vi.

Plant Species. New landscaping shall incorporate plant species that meet the following criteria:

(a)

Planting within thirty feet of buildings shall be fire-ignition resistant to the satisfaction of the fire marshal.

(b)

In compliance with Chapter 21.56 (Water Efficient Landscaping).

(c)

Non-invasive.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)

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A.

Allowed Modifications. Modifications to hillside development standards may be allowed through a special planned development (Chapter 21.11), development plan modification (Section 21.16.020), or site plan modification (Section 21.17.020) process. Table 21.81.050-1 (Hillside Modifications) outlines standards for which modifications may be requested.

Table 21.81.050-1: Hillside Modifications

Development

Site Plan

Standard Plan Special Planned Development Zoning Code Section Modification Modification

Paragraph 21.81.040(D)1. (Graded

Exceed maximum vertical height of Slopes and Retaining Walls), — May request May request graded slopes Table 21.81.040-1 (Slope and Retaining Wall Height)

Paragraph 21.81.040(D)1. (Graded

Exceed maximum height of retaining Slopes and Retaining Walls), May request May request May request walls up to 2 ft Table 21.81.040-1 (Slope and Retaining Wall Height)

Paragraph 21.81.040(D)1. (Graded

Exceed maximum height of retaining Slopes and Retaining Walls), — May request May request walls 2 ft or more Table 21.81.040-1 (Slope and Retaining Wall Height)

Minimum distance between — May request May request Subparagraph 21.81.040(D)1.b. retaining walls

Individual pad for 15—35% slope — May request May request Paragraph 21.81.040(C)2. (instead of stem walls)

Building with special building techniques (stem walls) on — — May request Paragraph 21.81.040(C)3. slopes over 35%

Height of stem wall May request May request May request Paragraph 21.81.040(D)2.

Landscape standards May request May request May request Paragraph 21.81.040(D)5.

B.

Modification Findings. In addition to the findings associated with the application (Section 21.11.060 [Special Planned Development]; Subsection 21.16.020(D) [Development Plan Modification]; Subsection 21.17.010(C) [Site Plan Modification]), all of the following findings can be made:

The modification preserves oak trees (as applicable); and

The modification does not involve individual pads on slopes over thirty-five percent.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)

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A.

General Standards for New Lots. The following standards shall apply to lots created through a tract map, parcel map, or reconfiguration of existing lots by a lot line adjustment:

No new lots shall be created that would necessitate locating the area of disturbance on existing slopes with an average of more than thirty-five percent.

The graded slopes and/or retaining walls between two adjacent lots shall be constructed on the lower lot; and

Between two adjacent lots, the property lines shall be located at the top of slopes.

B.

Development Plan Modification for Multiple Slope Categories. An application for a development plan modification (Section 21.16.020) may be submitted where a proposed tentative tract map includes areas that fall under several slope categories, and one or more of these areas are relatively small or narrow, to allow the application of standards applicable to the nearest predominant slope category rather than strict compliance with the minimum lot size and depth requirements (Table 21.33.030-1 [Development Standards for R-A, R-1, and R-1 Combining Districts]) if, in addition to the findings of Subsection 21.16.020(D), the review authority finds the modification would not result in a subdivision with non-uniform lot areas or non-orderly development.

(Ord. No. 1144 N.S., § 3(Exh. A), 10-1-2024)